Who can benefit me more?

What are the most important characteristics of my language partner?

For me, I have two choices to practice a language or improve my knowledge with a partner. The 1st choice, is to practice with an English native speaker who needs to practice my native language, so we can simply exchange our knowledge. The 2nd choice, is to search for an English learner in condition (should be on condition that/upon condition that) we are at the same level to get the best benefits of (out of/from) the time which we share together. I guess it is very important to agree (arrange) with each other for a convenient schedule according to our zone time(time zones), and arrange daily session according to our needs. The sessions should cover the possibility(possible, cause generally an adjective should be placed before a noun, rather then noun+noun, but it varies) weaknesses, and develop our strengthens(strengths, a noun should be used here). I can't make a fair assessment for(of) my current level and how far(much seems more fitting) I could improve the basic skills, so my partner should(could, it's a bit more polite and less demanding) help me to determine the main points which I need to focus on to overcome my mistakes.